Die for cutting tapered threads.



No. 861,682. PATENTBD JULY 30, 1907.

W. SHAW.

DI-E FOB. CUTTING TPERED THREADS.

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. MMIII-'mim Muang@ mu/unuumiia No. 861,682. 'PATBNTED JULY 3o, 1907.

W. SHAW.

DIE POR CUTTING TAPERED THREADS. PPLIOATION rILnn JULY so, loos.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

WILLIAM SI-IAW, OF EDWARDSVILLE, ILLINOIS, ASSIGNOR TO BIGNALL t KEELERMFG. COMPANY, OF EDWARDSVILLE, ILLINOIS, A CORPORATION.

DIE FOR CUTTING TAPERED THREADS.

Specification of Letters Patent.

Patented July 30, 1907.

Application filed July 30,1906. Serial No. 328,279.

To all 'whom it may concern:

Be it known that I, WILLIAM SHAW, a citizen of the United States oiAmerica, residing in Edwardsville, in the county of Madison and State oiIllinois, have invented certain new and useful Improvements in Dies forCutting Tapered Threads, of which the following is a full, clear, andexact description, reference being had to the accompanying drawing,forming part of this specification.

This invention relates to a new and useful improvement in dies forcutting tapered threads upon pipes, ctc., by the use of a plurality oidies or chasers mounted upon a revoluble head, which dies operate uponthe work to be threaded.

One object oi my invention is to produce a device of this characterwhich is strong, composed of few parts so that the same can beeconomically manufactured and is unlikely to become out of order.

Another object of the invention is to provide means whereby, after atapered thread has been cut upon the work to be threaded, the dies orchasers can be re leased from their binding tendency in the threads cutso that they can be withdrawn therefrom with little exertion on the partoi the operator.

Figure I is a face view of my improved die as an entirety. Fig. II is aside elevation of the same. Fig. III is a longitudinal section taken online III-III, Fig. I. Fig. IV is a detail view partly in section of aportion oi my die and the means employed for forming the taper of thethreads to be cut. Fig. V is a similar view to Fig. IV showing some ofthe parts in a changed position.

A represents a section of pipe upon which a tapered thread is to be cut,which pipe passes through and is secured to the work holder l by meansof set screws 2. This work holder l is oi a hollow cylindrical shape andis provided with an internally arranged screw thread 3 which has screwthreaded engagement with an exteriorly arranged thread 4 formed on ahollow cylindrical body 5. The work holder 1 is provided upon one endwith an outwardly disposed annular flange 6 and between which, and acollar 7 fastened to said work holder by a set screw 7 or any othersuitable means, is revolubly mounted a ring 8 carrying posts 9, thepurpose of which will hereinafter be described. Formed upon the outerend of and preferably integral with the hollow cylindrical body 5 is anannular flange or die holder 10 which is provided with a plurality oiradially disposed slots or guide-ways 11, and slidably mounted in whichare the dies or chasers 12, which dies or chasers are retained in theguide-ways l1 by plates 13 removably secured by screws as shown. Theinner ends of the chasers are provided with the usual thread cuttingthreads, while the outer ends thereoi extend beyond their supportingflange 10 andcoperate with eccentric faces 14 ormed on the inner facesof the posts 9. l

At least two of the posts 9 which I will designate by the letters x andy are provided with parallel inclined faces; that is, one ofthe faces xof the post x is provided with a face arranged at an angle to the axisoi the revoluble Chaser holding element, while the next adjacent face othe post y is formed with an inclined face y/ of a similar angle to theface x.

Secured to the periphery o the flange 10 and located between theparallel inclined faces x/ and y of the posts x and y (posts 9) is aconcentric bar of metal 15 which is somewhat shorter in length than isthe distance between the inclined-faces x and y/ and is designed tocontact with the former or latter when the Chaser holder is rotated inthe right-hand or left-hand direction respectively and imparts motion tothe ring 8 and its carried posts 9. This bar 15 is longitudinallyadjustable by means oi a slot 15l through which its securing means, inthe form of a screw 16, passes. The purpose of the adjustment of thisbar l5 is to increase or diminish the distance between its ends andthedies or chasers, whereby the cutting ends of the dies or chasers will,due to their position against the eccentric faces 14 of the posts 9, bea greater or less distance in the path oi the work to be threaded,whereby, upon the same work, a thread of greater or less depth can becut.

17 indicates sockets formed on the flange 10 which are designed toreceive handles by which said flange and its carried chasers or dies canbe turned.

In the practical use o my invention the operation of the device is asfollows: The pipe or other object to be threaded is clamped to the workholder by means of the set screws 2 with its extreme outer end injuxtaposition to the cutting inner ends of the dies or chasers, whilethe outer ends of said dies or chasers bear against the eccentric facesoi the posts 9 of the ring 8. The die or Chaser holder is then rotatedin the proper direction to cut a thread, which causes the ring 8 and itscarried posts 9 to also rotate, due to the Contact of the bar orprojection 15 with one of vsaid posts, and due to the screw threadedengagement of the die holder with the work holder, the former is drawninwardly and as the bar l5 which is carried by said die holder is alsodrawn inwardly its coperation with the inclined face a" of the post x(9) causes all of the posts 9 and their supporting ring 8 to rotate at aslightly greater speed than does the die holder, whereby the dies orchasers gradually recede from a point on the eccentric faces of theposts 9 nearest the axis oi the work-which position they occupy when thethread was started-to a point on said eccentric face of greater distancefrom the axis of the work, whereby the cutting inner ends of the dies orchasers are gradually moved from their initial position where they werecutting the maximum depth thread until they finally fail to cut a threadat all upon the work.l After this tapered thread has been cut upon thework and it is desired to remove the dies therefrom, the die holder isrotated in a reverse dierction, the initial movement of which causes thebarl, which as before stated is somewhat shorter than the distancebetween the faces x and y of the posts 9, to move a given distance andthen Contact with the inclined face y of the post y, whereuponretrogressive movement to the ring 8 and its carried posts is imparted.It will be understood that the movement of the bar l from the positionthat it occupied when cutting a thread to the A position it occupies asjust above described, permits the die holder to rotate a short distanceand relieves the dies or chasers from Contact with the eccentric facesoi the posts 9 and permits said dies or chasers to move outwardly,whereby their binding tendency in the threads cut in the work isrelieved.

I claim:

l. In a screw cutting die the combination of a Work holder, a Chaserholder having threaded engagement with said work holder and rotatable inrelation thereto, a ring mounted for rotation on said Chaser holder andprevented from endwise movement with relation to the Chaser holder,

and ,having an interior eccentric face against which a chascr carried bysaid Chaser holder is adapted to bear so i as to be forced inwardlytoward the axis of the Chaser' holder, and engaging parts'on saidringand said Chaser holder so constructed and arranged that the ring isrotated in relation to the Chaser holder While the Chaser holder and thering are being rotated combinedly g. substantially as set forth.

2. In a screw cutting die the combination of a work holder7 a Chaserholder having threaded engagement with as to be forced inwardly towardthe axis of the Chaser holder, and a face inclined to the axis of saidring, and means Vcarried by said chaser` holder adapted to ride againstsaid inclined face so as to rotate said ring in relation to said Chaserholder While said parts are rotated combinedly; substantially as setforth.

3. In a screw cutting die, the combination of a work holder, a Chaserholder having threaded engagement with said Work holder and rotatablerelative thereto, a revoluble ring surrounding said Chaser holder andprevented from endwise movement and having an eccentric face at theinside of its wall against which a chaser carried by said holder isadapted to bear and having a pair of inclined faces located parallelwith each other and a bar fixed to said Chaser holder and adapted toride against either of said inclined faces to rotate said ring; said barbeing shorter than the distance between said inclined faces,substantially as and for the purpose set forth.

el. In a screw cutting die, the combination of a Work holder, a Chaserholder having threaded engagement with said work holder and rotatablerelative thereto, a revoluble ring surrounding said chaser holder andprevented from cndwise movement and having an eccentric face at theinside of its Wall against which a Chaser carried by said holder isadapted-to bear and having a pair of inclined faces located parallelwith each other and a bar adjustably secured to said Chaser holder andadapted to ride against either of said inclined faces to rotate saidring; substantially as set forth.

5. In a screw cutting die, the Combination with a support, of arevoluble Chaser Carrying-element having screw threaded engagement withsaid support, a revoluble ring mounted upon said support and providedwith inwardly disposed eccentric faces for cooperation with Chaserscarried byrsaid revolu-blre element; said Chaser supporting element andrevoluble ring being provided with/engaging parts Constructed andarranged tol cause rotative movement of said ring at a different speedfrom that of the Chaser Carrying element as the latterl 'Vs rotated,substantially as set forth.

, wiiligiAM sHAw. In presence of-' f f "i E. S. KNIGHT, y

BLANCHEv HOGAN.

